A young woman with recurrent vesicles on the lower lip: Fixed drug eruption mimicking herpes simplex

A 23-year-old woman presented with recurrent herpetiform vesicles of the lower lip, but all diagnostic measures for herpes virus infection including herpes viridae specific PCR were negative. Medical history revealed that she also had chronic recurrent vulvovaginal candidiasis, which had been treated with various regimes, including repetitive applications of fluconazole. Consequently, fluconazole-induced fixed drug eruption was suspected, but skin tests performed with fluconazole remained without response. Consecutive repeated oral provocation tests with fluconazole were carried out and resulted in the development of burning herpetiform vesicles of the lower lip. Histopathology revealed a subepidermal and superficial perivascular infiltrate, basal vacuolated and apoptotic keratinocytes, intra-epidermal lymphocytes and intra-epidermal multilocular vesicles. Together with the clinical history and picture, fluconazole-induced fixed drug eruption mimicking labial herpes simplex virus infection was diagnosed. Oral provocation tests with an alternative systemic antifungal treatment, itraconazole, were well tolerated, systemic therapy with itraconazole was initiated, and no further labial vesicles developed.